Earth's Water Supply

What percentage of Earth's water is salt water?

• 91%

• 97%

• 50%

• 71%

Salt water oceans make up about ​ (a)   of the Earth's surface, while land makes up about ​ (b)   .

• 71%
• 29%
• 91%
• 9%
• 60%
• 50%
• 40%

True or False: Salt water is only found in oceans.

Answer explanation

Salt water can also be found in lakes, like the Great Salt Lake in Utah.

What percentage of Earth's water is freshwater?

• 1%

• 3%

• 6%

• 10%

Only about ​ (a)   of water is available as surface water.

• 1%
• 2%
• 5%
• 10%

Where is most of Earth's freshwater found?

• frozen in glaciers and polar ice caps

• underground in aquifers

• in streams, rivers, and lakes

• in Earth's oceans

Where is most of Earth's available (not frozen) freshwater stored?

• glaciers

• lakes

• oceans

• underground

Which of the following are common sources of surface water? (three answers)

• bays

• gulfs

• lakes

• rivers

• streams

Groundwater often gathers in ​ (a)   .

• aquifers
• lakes
• oceans
• glaciers

​ (a)   causes water vapor to gather into clouds of varying shapes and sizes.

• Condensation
• Precipitation
• Evaporation
• Runoff